<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #app {
            color: aquamarine;
            font-size: 14px;
        }
        #app {  
            color: pink;
        }
    </style>
</head>
<body>
    <!-- 重复的样式会被最新的覆盖 -->
    <div id="app">
        层叠性
        <!-- 可以继承的样式 text- / font- / line- / color -->
        <div>继承</div>
    </div>
</body>
</html>